The present invention generally relates to three-dimensional (“3D”) imaging. More specifically, the present invention describes a method and system for progressive multi-resolution three-dimensional fluoroscopic image reconstruction using automatic region of interest.
Two fields of medical imaging that require dynamic reconstruction include functional imaging and interventional imaging. Functional imaging can include, for example, positron emission tomography (“PET”) and single photon emission computed tomography (“SPECT”). Interventional imaging can include, for example, fluoroscopic computer tomography (“Fluoro CT”).
Modern medical imaging systems frequently employ mobile C-arm fluoroscopy systems to facilitate a variety of diagnostic and interventional radiological procedures. While these systems typically obtain two-dimensional (“2D”) fluoroscopic grayscale images, more recent mobile and advanced fixed-room fluoroscopic systems have utilized computer tomography to create 3D images from a plurality of 2D images. These more recent systems increase the convenience and decrease the cost of obtaining 3D image scans at times before, during and after a medical procedure.
However, the value of these 3D fluoroscopic image scans is limited by some key factors, including interference with a workflow in an operating room. For example, the time required for set-up of the system, image data acquisition, and image reconstruction from a plurality of 2D images into 3D image data can, in many instances, offset any benefits derived from obtaining the 3D image data.
In addition, conventional 3D image reconstruction does not provide high quality image information for quite some time. For example, conventional 3D image reconstruction is conducted by updating 3D image information on a view-to-view basis. FIG. 7 illustrates a 3D image reconstructed on a view-to-view basis. FIG. 7 includes a progression of six images 710 through 760. Each image corresponds to a reconstructed 3D image after an amount of time listed in each image. For example, image 710 represents an image acquired, reconstructed and displayed after two seconds of image acquisition and reconstruction. Subsequent images represent images reconstructed with image data acquired after the display of the previous image. For example, image 720 represents image 710 updated with image data acquired after image 710 is displayed. In this way, images 720, 730, 740, 750, and 760 represent reconstructions of previous images as additional data is acquired and reconstructed. Such a procedure is known as image reconstruction on a view-by-view basis
However, the updating of image information on a view-by-view basis includes several drawbacks. A major problem with such a procedure is the failure to provide any significant image detail and/or quality until all image data for the entire image view has been fully acquired and reconstructed, as apparent from FIG. 7. For example, no significant image detail is available until at least images 750 and 760. Approximately no image detail is available in previous images 710, 720, 730 and 740.
In addition, view-by-view updating causes strong aliasing artifacts to exist in the images up to the time when the very last fluoroscopic image projection within an angular range sufficient for complete image reconstruction is backprojected into the reconstructed image.
In addition, imaging modalities considered as “diagnostic imaging”, such as CT, magnetic resonance (“MR”) and radiography imaging, for example, obtain images that may not be reviewed for hours, days or even weeks after image acquisition. In contrast, mobile C-arm imaging systems are traditionally used for interventional imaging which can provide for near real-time acquisition and review of 2D fluoroscopic images. In an ideal situation, 3D tomographic image information would also be available in near real-time. However, until technology provides cost-effective solutions, a method and system for significantly reducing the amount of time required to calculate and display high quality 3D images is required. Such a need can be met by utilizing progressive multi-resolution image reconstruction techniques alone or in conjunction with a variety of manual and/or automated region-of-interest selection techniques, for example.
Thus, a need exists for a method and system for progressive multi-resolution three-dimensional image reconstruction using region of interest information. Such a method and system can provide for a significant reduction in the amount of time required to display high quality 3D image information. For example, such a method and system can provide for the commencement of progressive visualization of image reconstruction almost immediately after data acquisition is completed.